The present invention relates to a system for gathering data representing the number of event occurrences in an electronic computer.
Recently, with the complication and the variety of computer art, it is necessary to improve the performance of programs executed by the computer and/or computer itself for high speed processing.
In order to improve the performance thereof, it is necessary to measure the present performance of an electronic computer system.
This measurement can be accomplished in a digital electronic computer by gathering data representing the number of executions of each of various kinds of instructions in programs or the number of occurrences of each of events corresponding to status changes occuring in the computer.
In a prior art gathering system, data is gathered such as the number of executed instructions and the number of memory requests by connecting measurement terminals of general counters with signal terminals derived from logic cards in the computer or by assembling counters in the computer.
A prior art system using such general counters has the following disadvantages.
(1) Gathered data become meaningless when the measurement terminals of the general counters are erroneously connected.
(2) In order to collect data of various kinds, the same processing must be repeated.
(3) It is impossible to collect a large amount of data at the same time.
(4) As logic circuits are formed with Large Scale Integration (LSI), the number of the signal terminals derived from the logic card is reduced. Therefore, desired signals for measurement are not obtained from the signal terminals.
On the other hand, in a case that counters are assembled in the computer, it is very expensive to provide a multiple of counters for counting the number of occurrences of each event. Furthermore, it is difficult to assemble such counters in the computer.